1. Field of the Invention
The invention relates to a rotary joint for underwater operation, particularly for use in a system for generating energy from waterpower, the joint comprising two rotationally symmetrical, mutually concentric connecting elements rotatable in opposite directions about a common axis, further comprising an annular gap disposed between the two connecting elements, and at least one row of rolling elements rolling along a race on each of the first and the second connecting elements, and to seal the annular gap, a sealing device having at least one sealing ring fixed to the first connecting element and is provided with a circumferential sealing lip extending along a lead-in surface.
2. Description of the Prior Art
More than half of the earth's surface is covered by water. Many untapped resources therefore still exist both on and under the water, whether mineral resources, water power, or routes of transportation. High technology is a necessity for the exploitation of these resources, be it in the form of drilling platforms, tidal power plants, ships, etc. In cases where there is an exchange of energy with water, for example, where a mechanical system expends drive power, as in the case of ships, or where it is driven, as in the case of tidal power plants, this generally requires relative movement between various machine or system parts that are in the water, for example, the propellers or impellers of ships, the turbines of tidal power plants, etc. A problem that always arises in this context is how to seal the moving parts with respect to one another.
Assuming that 100% sealing is desired, if at all possible, this can usually be achieved only with high contact forces. This, in turn, leads to high friction and thus to high wear, thereby shortening maintenance intervals and especially service life. The lead-in surfaces of the seals are frequently affected as well, with the result that maintenance work is not limited to the replacement of a seal, but entails replacing entire components of the system.
From the disadvantages of the prior art comes the problem initiating the invention, that of improving a rotary joint for underwater operation of the cited species so as to keep maintenance work to a minimum.